As a conventional disc brake and a caliper slide mechanism, for example, Patent Document 1 discloses a pin slide type disc brake in which a slide pin is fixed to an ear portion of a caliper by a bolt that passes through the ear and screwed in the slide pin, the slide pin is inserted in a pin hole of a support member, and the caliper is thereby supported slidably in the disc axial direction. In the pin slide type disc brake, a slit is provided on an end surface on a slide pin mounting side of the ear of the caliper, a head portion of the slide pin that has two parallel flat surfaces is arranged in the slit, and the flat surfaces of the slit that face each other thereby prevent rotation of the slide pin.